• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.6
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• pp.9-14
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• 2007

In this paper, a rotating tool clamping device was developed based on a shape memory alloy(SMA) and its feasibility as a tool holder was experimentally explored. The SMA-based device was able to alter clamping to unclamping through temperature control within 1 second. The means and repeatability(${\sigma}$) of the tool clamping force were 185.5N and 6N respectively and its drifts were less than 3% for an hour. Considering the temperature hysteresis of the SMA-based tool clamping device, it is necessary to heat the SMA ring to around $50^{\circ}C$ after tool change to obtain more clamping force.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.10a
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• pp.199-202
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• 2003

The dynamic characteristics of composite tool bars depend on the clamping conditions such as clamping force, stiffness and surface characteristics of clamping parts as well as the basic structures. Therefore, in this work, the effects of clamping part conditions on the dynamic characteristics of cantilever type composite machine tool structures with clamped joint were investigated because the cantilever type machine tool structures are ideal cases for composite application to increase the natural frequency and damping of structures. New design of the clamping part was developed in order to improve shear properties of the clamping part and dynamic characteristics of composite tool bars. From FE analysis and Impulse response tests, dynamic characteristics were obtained with respect to the clamping part conditions of the new design.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.5
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• pp.70-75
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• 2008

This paper describes a tool-clamping/unclamping mechanism for application of a micro-spindle. The mechanism is based on one-way shape memory effect and interference-fit. The corresponding mathematical models and a few considerable design parameters are mentioned in this paper. Especially, necessary conditions for the clamping and unclamping operation are investigated through finite element analysis. The analysis results show that the differences between the diametral deformations of the tool holder in high temperature and that in low temperature are increased according to amounts of the interference. Thus the less interference between the tool-holder and the ring, the less tolerance to allow the clamping and unclamping operation because the inner diameter of the tool holder in high temperature should be smaller than the diameter of the tool shank, and that in low temperature should be larger than the diameter of the tool shank. In addition, the design for maximization of clamping force are investigated based on finite element analysis. The results show that the more amounts of the interference, the more clamping force. As the result, the interference should be considered as a important factor to maximize the tool clamping force.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.5
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• pp.710-715
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• 2010

This study developed an automatic tool change system of the SMA-based tool clamping device for applications of micro-machine tools. This paper first describes clamping and unclamping procedures of the automatic tool change system and its basic configuration. Second, it presents fabrication techniques of components, such as a heating/cooling system and a tool loader. Finally, it describes automatic tool change test conducted with a prototype in which the fabrication techniques of components were employed. As the results of the test, times needed for clamping and unclamping operations were estimated to 18(s) and 8(s) respectively. The experimental results confirm that the proposed automatic tool change system can be sucessfully applied to micro-machine tools.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.1
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• pp.16-20
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• 2008

This paper presents the construction of micro tool clamping device using a Ni-Ti shape memory alloy(SMA) ring. Clamping force of the device is produced by elastic force of the SMA reverted to its original shape in normal temperature. Phase transformation of the SMA was realized by temperature control using a peltier element. Prototype of the SMA tool clamping device was fabricated and examined its clamping force and clamping/unclamping operation.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.831-832
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• 2008

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.25 no.1
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• pp.1-6
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• 2016

Micromanufacturing is a useful system for reducing energy consumption. For micromanufacturing, tool clamping and workpiece clamping are important components to realize the machining process. Therefore, a shape memory alloy (SMA) ring type tool holder is developed. In addition, this holder needs cooling and heating processes to execute the tool clamping process. This study suggests a cooling/heating device based on peltier elements. The device will be applied to the heating/cooling process of an automatic tool changer (ATC) for the SMA tool holder. This study introduces the configuration and operating principle of the proposed ATC system. The description and prototype evaluation of this system were given. Plastic bolt and aluminum block were selected to enhance the cooling performance, and the installed tool was changed in 17 s during the experiments.

• Fisheries and Aquatic Sciences
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• v.17 no.3
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• pp.339-344
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• 2014

PCR amplification with universal primer is a useful tool for speciation of symbionts in marine eukaryote coupled with robust separation method such as denaturing high performance chromatography (DHPLC). To overcome the biased amplification, clamping PCR is recommended to suppress the amplification of host gene. In this study, we evaluated the efficiency of rare gene detection for two kinds of clamping probes which were successfully utilized for eukaryotic symbiont analysis: C3 linked nucleotide (C3) and peptide nucleic acid (PNA). PNA was 3-4 orders of magnitude higher than that of C3 tested in clamping efficiency and rare gene detection. This represented that PNA could be a more competent clamping probe for the enhancement of PCR amplification for rare symbiont genes.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.6
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• pp.889-894
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• 2010

Conventional shrink-fit tool holders have positive features, such as high accuracy, high strength, high stiffness and low sensitivity to centrifugal forces, but they require heavy investments for heating and cooling equipment. Generally the heating equipment has to heat the tool holder up to $200{\sim}300^{\circ}C$ for tool changes. This paper introduces a novel shrink-fit tool holder that is able to unclamp a tool at $40{\sim}50^{\circ}C$. This feature makes it possible to switch between the clamped and unclamped states by using a simple device, which has lower power, smaller size and lower cost than the heating equipment of the conventional shrink-fit tool holders. The proposed shrink-fit tool holder is able to expand its tool hole by using the shape memory alloys which are integrated in the tool holder body. Performances of the SMA shrink-fit tool holder were evaluated experimentally. The experimental results confirm that the proposed tool holder is feasible in aspects of clamping/unclamping operations, clamping force and repeatability of tool setup.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1749-1752
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• 2005

High speed machining has become the main issue of metal cutting. Due to increase of the rotational speed of the spindle, problems, such as the run-out errors, reduced stiffness, must be overcome to improve the machining accuracy. In order to solve the problems, it is important to determine the appropriate clamping unit and tooling system. This paper presents an investigation into an evaluation of contact interval which is the interface between spindle taper hole and tool holder shank of the spindle. Finite element analysis is performed by using a commercial code ANSYS according to variation of clamping forces and rotational speeds. This paper proposed fit tolerance in order to evaluate the effects of clamping force and rotational speed on the contact interval in the spindle interface. From the finite element results, it has been shown that the rotational speed rather than clamping force mostly influence on the variation of the contact interval.